Target type: molecularfunction
Catalysis of the reaction: ATP = 3',5'-cyclic AMP + diphosphate, stimulated by calcium-bound calmodulin. [EC:4.6.1.1, GOC:mah]
Calcium- and calmodulin-responsive adenylate cyclase activity refers to the enzymatic process by which adenylate cyclase, a transmembrane protein, is activated by the binding of calcium ions (Ca2+) and the calcium-binding protein calmodulin. This activation leads to the conversion of adenosine triphosphate (ATP) into cyclic adenosine monophosphate (cAMP). cAMP acts as a second messenger, relaying signals from the cell surface to the interior of the cell, ultimately regulating a wide range of cellular processes.
Specifically, when Ca2+ levels rise within the cell, they bind to calmodulin. This complex then interacts with the regulatory domain of adenylate cyclase, leading to a conformational change that activates the catalytic domain of the enzyme. The activated enzyme then catalyzes the formation of cAMP from ATP.
The molecular function of calcium- and calmodulin-responsive adenylate cyclase activity involves several key steps:
1. **Ca2+ binding to calmodulin:** Calmodulin, a small, highly conserved protein, binds to Ca2+ with high affinity. The Ca2+-calmodulin complex then undergoes a conformational change.
2. **Complex interaction with adenylate cyclase:** The Ca2+-calmodulin complex binds to a specific site on the regulatory domain of adenylate cyclase.
3. **Conformational change and activation:** This binding event triggers a conformational change in the adenylate cyclase molecule, leading to the activation of its catalytic domain.
4. **cAMP synthesis:** The activated adenylate cyclase catalyzes the conversion of ATP to cAMP.
5. **Cellular signaling:** cAMP then acts as a second messenger, activating downstream signaling pathways involved in various cellular processes, including gene expression, cell growth, and metabolism.
Overall, calcium- and calmodulin-responsive adenylate cyclase activity plays a crucial role in cellular signaling by converting calcium signals into cAMP signals. This process is essential for regulating a diverse range of cellular functions.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Adenylate cyclase type 1 | An adenylate cyclase type 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q08828] | Homo sapiens (human) |
| Adenylate cyclase type 8 | An adenylate cyclase type 8 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P40145] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| 1,3-dipropyl-8-cyclopentylxanthine | DPCPX : An oxopurine that is 7H-xanthine substituted at positions 1 and 3 by propyl groups and at position 8 by a cyclohexyl group. | oxopurine | adenosine A1 receptor antagonist; EC 3.1.4.* (phosphoric diester hydrolase) inhibitor |
| theophylline | dimethylxanthine | adenosine receptor antagonist; anti-asthmatic drug; anti-inflammatory agent; bronchodilator agent; drug metabolite; EC 3.1.4.* (phosphoric diester hydrolase) inhibitor; fungal metabolite; human blood serum metabolite; immunomodulator; muscle relaxant; vasodilator agent | |
| caffeine | purine alkaloid; trimethylxanthine | adenosine A2A receptor antagonist; adenosine receptor antagonist; adjuvant; central nervous system stimulant; diuretic; EC 2.7.11.1 (non-specific serine/threonine protein kinase) inhibitor; EC 3.1.4.* (phosphoric diester hydrolase) inhibitor; environmental contaminant; food additive; fungal metabolite; geroprotector; human blood serum metabolite; mouse metabolite; mutagen; plant metabolite; psychotropic drug; ryanodine receptor agonist; xenobiotic | |
| colforsin | Colforsin: Potent activator of the adenylate cyclase system and the biosynthesis of cyclic AMP. From the plant COLEUS FORSKOHLII. Has antihypertensive, positive inotropic, platelet aggregation inhibitory, and smooth muscle relaxant activities; also lowers intraocular pressure and promotes release of hormones from the pituitary gland. | acetate ester; cyclic ketone; labdane diterpenoid; organic heterotricyclic compound; tertiary alpha-hydroxy ketone; triol | adenylate cyclase agonist; anti-HIV agent; antihypertensive agent; plant metabolite; platelet aggregation inhibitor; protein kinase A agonist |
| sch 23390 | SCH 23390 : A benzazepine that is 2,3,4,5-tetrahydro-3-benzazepine bearing a phenyl substituent at position 1, a methyl substituent at position 3, a chloro substituent at position 7 and a hydroxy substituent at position 8. SCH 23390: a selective D1-receptor antagonist | benzazepine | |
| sk&f-38393 | (R)-SKF 38393 : A 1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol that is the R-enantiomer of SKF 38393. | 1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol |